Acid rain and soil microbial activity: effects and their mechanisms

Journal Article · Sat Jan 01 04:00:00 EST 1983 · J. Environ. Qual.; (United States)

DOI:https://doi.org/10.2134/jeq1983.00472425001200010024x· OSTI ID:5534618

Killham, K; Firestone, M K; McColl, J G

In this investigation, our aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pH 6.4) planted with Ponderosa pine seedlings was exposed to simulated rain (pH 2.0, 3.0, 4.0 and 5.6) with ionic composition reflecting that found in northern California, corresponding to 15 cm of precipitation over a 12-week period. After exposure, the soils were collected in two samples (top 1 cm and 4 to 5 cm), which were assayed separately for respiration and enzyme activities (urease, phosphatase, dehydrogenase, and arylsulfatase). Changes in microbial activity were most significant in surface soils. Only the pH 2.0 input caused inhibition of both respiration and enzyme activities. The overall microbial response to the pH 3.0 and 4.0 acid regimes was one of stimulation, although the response of individual enzymes was more varied. In surface soils receiving the pH 3.0 input, for example, urease activity was unaffected while arylsulfatase and phosphatase were increased and decreased respectively. Therefore, individual microbial processes will have different sensitivities to acid rain. Although changes in C-availability in the exposed soils are documented, changes in the supply of N are evaluated as the major mechanism through which simulated acid rain affects soil microbial activity.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 5534618
• Journal Information: J. Environ. Qual.; (United States), Journal Name: J. Environ. Qual.; (United States) Vol. 12:1; ISSN JEVQA
• Country of Publication: United States
• Language: English

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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID RAIN
ACIDIFICATION
AIR POLLUTION
AMIDINASES
ATMOSPHERIC PRECIPITATIONS
AVAILABILITY
BIOLOGICAL EFFECTS
CALIFORNIA
CARBON
CONIFERS
ELEMENTS
ENVIRONMENTAL EFFECTS
ENZYME ACTIVITY
ENZYMES
ESTERASES
FEDERAL REGION IX
HYDROLASES
INHIBITION
MICROORGANISMS
NITROGEN
NON-PEPTIDE C-N HYDROLASES
NONMETALS
NORTH AMERICA
OXIDOREDUCTASES
PH VALUE
PHOSPHATASES
PINES
PLANTS
POLLUTION
RAIN
RESPIRATION
SEEDLINGS
SOILS
TREES
UREASE
USA